Sample output from Andrew Brown’s excellent Minecraft Overviewer.
Updated missing url https://cdn.rawgit.com/simplegeo/polymaps/v2.2.0/polymaps.min.js to https://cdn.jsdelivr.net/gh/simplegeo/polymaps/v2.2.0/polymaps.min.js
https://cdn.rawgit.com/simplegeo/polymaps/v2.2.0/polymaps.min.js